The present invention relates to elevator systems that employ sliding doors that are suspended above a door sill. In particular, the invention provides a door sill assembly for guiding the lower portion of one or more sliding elevator doors without the need for a slot in the door sill. Such slots typically accumulate debris and which often requires the use of a guide having a shape complementary to the slot. The present invention may be used with either hoistway doors or elevator car doors.
A typical elevator system employs sliding hoistway doors and sliding car doors that are suspended from overhead rails. In order to prevent the bottom of the doors from swinging into or away from the hoistway (or into and out of the elevator car), while at the same time allowing the doors to slide between an opened and closed position, one or more door guides are fastened to a lower portion of the door. Traditionally, door guide(s) ride in a upward facing slot that is located in a door sill. The guides have a shape complementary to the shape of the slot. This allows the door guide to slide along the slot but prevents the bottom of the door from swinging in a direction perpendicular to the sliding motion of the door.
Litter and debris often fall into the upward facing slot and impede proper operation of the door. To address this problem, at least with respect to sliding elevator car doors, some manufacturers have placed the slot under the floor of the elevator car or in the side of a car sill. While these designs are intended to reduce the amount of litter that accumulates in the slot, in some applications, litter can still find its way into the slot and cause maintenance problems. Moreover, these designs require the use of a door guide having a shape that is complementary to the shape of the slot (or at least complementary to a portion of the slot). The guide must also be small enough to fit in the slot. Yet if the guide is made too much smaller than the slot, the bottom of the door will be able to swing in and out and this swinging could, under some circumstances, cause the door to bind or otherwise prevent the door from operating properly.
The present invention provides a door sill assembly for guiding a lower portion of a sliding elevator door in a standard elevator system. The sliding door has a door surface and slides horizontally in a direction parallel to the door surface. The sliding door may be a hoistway door or a car door.
In one embodiment of the invention, a sill plate is installed horizontally in the threshold of a hoistway opening. The sill plate is preferably mounted below the sliding door and in a direction that is parallel to the door surface. A horizontal rail is mounted under the sill plate in a direction approximately parallel to the door surface. The rail may be mounted on the sill support assembly on which the sill plate may be mounted, or the rail may be an integral part of the sill plate. The rail preferably has first and second sliding surfaces. A pair of door guide surfaces, i.e., a first and second door guide surface, straddle the rail so that the rail is located between the sliding surfaces. The first door guide surface engages and can slide along the first sliding surface and the second door guide surface engages and can slide along the second sliding surface. Thus, the guides surfaces can slide along the rail, but cannot move perpendiculary toward and away from the rail.
The guide surfaces may be connected to a bracket, which in turn may be fastened, either directly or indirectly, to a lower portion of the door. The door is thus free to slide along the rail, but door is restricted from moving toward and away from the sliding surfaces and consequently toward and away from the hoistway. In one embodiment, the sliding surfaces are preferably vertical surfaces and are preferably parallel to the door surface. The sliding surfaces may, however, be oriented in any direction that allows door to slide opened and closed but restricts the bottom of the door from swinging toward and away the hoistway.
The present invention also employs a safety that prevents the sliding door(s) from moving in a direction perpendicular to the door surface in the event the door guide surfaces, brackets or other components fail. The safety has first and second safety surfaces that are capable of engaging the first and second sliding surfaces of the rail in the event a primary door guidance system, such as the one described herein, fails. Because the safety does not ordinarily engage the rail, it may be manufactured from materials that are not necessarily suitable for use as door guide surfaces. Typically, but not necessarily, the safety surface would engage the appropriate sliding surface to prevent the door from swinging away from the door sill assembly.
The present invention also provides a telescopic sliding door assembly comprising an fast-speed door and a slow-speed door. The fast-speed door has a door surface that faces some or all of the slow-speed door. This assembly may be a two-speed arrangement. The fast-speed door may employ the above-described door sill assembly as a guidance means. The slow-speed door, which moves preferably at approximately half the speed of the fast-speed door, is guided as follows. A downwardly-facing dual track assembly is horizontally mounted on the slow-speed door. It is preferably mounted on a lower portion of the door surface, which faces the fast-speed door. The dual track assembly preferably has two parallel horizontal channels that face downward, i.e. the opening in the channel faces downward. The first channel slides over and is guided by a stationary slow-speed door guide that is mounted to and extends vertically upward from the sill plate or the floor surface. The second channel rides over and is guided by a moving slow-speed door guide that is mounted on a lower portion of the fast-speed door with a bracket. As the fast-speed door moves so does the moving slow-speed door guide. Accordingly, as the slow-speed door moves, it is guided by the stationary slow-speed door guide and by the moving door guide.